I agree with approximately all of you.
Even if I do think we need a complete change with the rank system.

Stars are one solution. Keep them.

If we want to go till 5000+, we need 5 stars. it would be better than adding 2, 3 or 4 stars colors. Moreover, if we keep the same colors but change the order, that would disappoint a lot of great players (i.e. you have currently your 1st gold star with 500 points, if now you need 3000 to get them, I personnaly would feel bad...). So we need to keep the first colors.

I do not know exactly how the current stars system works, but here is my proposition.

6000+ points : I let your imagination to give an ULTIMATE star, something so marvellous that nobody knows the existence and nobody can imagine what it can be (i propose the NO(OB) star).

Some explanations :

I added the green stars for precise reasons. You can notice that green stars don't affect much the current light blue ranking. The main aim to these stars are to make new people on RS stay so that they can appreciate the game until they get 100 points. If you feel to win fast, you are more likely to stay in the game

With this system, you can get new stars until 6000 points so it will motivate people to win again and again.

The current ranking system is partly preserved with this new one, so I don't think people would lose a star.